US4535595A - Cooling device for a low temperature magnet system - Google Patents

Cooling device for a low temperature magnet system Download PDF

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Publication number
US4535595A
US4535595A US06/577,699 US57769984A US4535595A US 4535595 A US4535595 A US 4535595A US 57769984 A US57769984 A US 57769984A US 4535595 A US4535595 A US 4535595A
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United States
Prior art keywords
further characterized
cooling apparatus
refrigerator
coil
cooling
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Expired - Lifetime
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US06/577,699
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English (en)
Inventor
Tony W. Keller
Wolfgang Muller
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Bruker Biospin GmbH
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Bruker Analytische Messtechnik GmbH
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Priority claimed from DE19833304375 external-priority patent/DE3304375A1/de
Priority claimed from DE19833308157 external-priority patent/DE3308157A1/de
Application filed by Bruker Analytische Messtechnik GmbH filed Critical Bruker Analytische Messtechnik GmbH
Assigned to BRUKER ANALYTISCHE MESSTECHNIK GMBH, reassignment BRUKER ANALYTISCHE MESSTECHNIK GMBH, ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KELLER, TONY W., MULLER, WOLFGANG
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Publication of US4535595A publication Critical patent/US4535595A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F6/00—Superconducting magnets; Superconducting coils
    • H01F6/04—Cooling
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
    • G01R33/381—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field using electromagnets
    • G01R33/3815—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field using electromagnets with superconducting coils, e.g. power supply therefor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/38—Systems for generation, homogenisation or stabilisation of the main or gradient magnetic field
    • G01R33/389—Field stabilisation, e.g. by field measurements and control means or indirectly by current stabilisation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S505/00—Superconductor technology: apparatus, material, process
    • Y10S505/825—Apparatus per se, device per se, or process of making or operating same
    • Y10S505/888—Refrigeration
    • Y10S505/892—Magnetic device cooling

Definitions

  • the invention concerns a cooling device for a low temperature magnet system in which the magnet coil is contained in an evacuated outer jacket surrounded by at least one intermediate shield and in which a refrigerator is provided and arranged on the outer jacket, which refrigerator cools the at least one intermediate shield through a cooling arm passing through the outer jacket.
  • superconducting magnets are being employed in an ever increasing extent in place of classical iron magnets. These superconducting magnets consist essentially of a magnet coil, wound of superconducting wire, placed in a cryostat which keeps it at an operating temperature of about 4 K.
  • solenoid coils are used which are located in a container for liquid helium.
  • This container is surrounded by a further container filled with liquid nitrogen.
  • heat shields maintained at a temperature lying between the boundary temperatures and serving to pre-cool the inner-most container containing the liquid helium.
  • the superconducting coil has a current applied to it and then, in a known way, it is short-circuited so that the introduced current can flow practically endlessly in the superconducting coil so long as its superconductance is maintained.
  • the cost of driving such a superconducting magnet is decided by the consumption of the mentioned liquid gases, namely liquid nitrogen and liquid helium. If it is possible to keep the evaporation rate of these liquid gases to a low value the cost of driving a superconducting magnet can be kept low so that--in addition to the magnetic field properties--generally favorable conditions as to operating costs are possible in comparison with classical iron magnets.
  • a cooling system customarily referred to as a refrigerator
  • a refrigerator to the outer shell of the superconducting magnet system.
  • These known refrigerators make use of a cooling arm which extends through the outer shell of the cryostat until it reaches one or more inner containers or the protective shields and actively cools these.
  • the cooling arm, or the cooling arm with one or further projecting cooling fingers therefore keeps the inner containers or protective shields at such low temperatures that the evaporative loss of the liquid gases reaches an especially low value.
  • Known refrigerators have a cooling head, arranged outside of the outer shell of the magnet system, containing a motorized drive with pistons or the like.
  • This motorized drive is preferably driven by pressurized air delivered from a more remote stationary compressor through a flexible line.
  • the movable piston or pistons located in the cooling head have a direct effect on the magnetic field insofar as they set the superconducting magnet system into vibration, since through the movement of the metallic pistons disturbing fields are introduced.
  • Superconducting magnet systems of the above described kind are further preferably used for the measurement of magnetic resonances, for example magnetic nuclear resonance.
  • magnetic resonances for example magnetic nuclear resonance.
  • disturbances of the mentioned kind produced by the motorized refrigerator drive have an especial effect because the motorized drive of the refrigerator works at relatively low frequencies and the disturbances originating from it cannot be rejected through customary stabilizing measures. This is also true in the case of the so called internal lock in which the magnet field is regulated with the help of a reference line of the nuclear resonance spectrum.
  • the named superconducting magnet system is kept in operation in "persistent mode", depending on circumstances, for years at a time. This is possible because the maintenance of the magnetic field in superconducting magnets is a loss free process, since because of the superconductance losses do not arise.
  • the refrigerator in the named arrangement is subject to mechanical wear so that such a long operating time is not possible with refrigerators available today. Consequently it is necessary to mechanically inspect the refrigerators at definite time periods. For such an inspection it is moreover necessary to warm it to room temperature in order, for example, to be able to replace O-rings or other seals or to replace other mechanical parts.
  • the invention has therefore as an object the provision of an apparatus which on one hand makes possible an especially low evaporation rate of the liquid gas by the use of a refrigerator, and which on the other hand avoids the described disadvantages resulting from the disturbances originating from the refrigerator.
  • This object is achieved in accordance with the invention by providing a sensor for detecting the magnetic and/or mechanical disturbance signals emitted by the motorized drive of the refrigerator, which sensor controls at least one winding or coil compensating for the disturbing field effective in the test space.
  • the inventive cooling device has the especial advantage in the case of high resolution nuclear resonance measurement that it permits the use of actively cooled protective shields.
  • a detecting coil arranged in the vicinity of the refrigerator serves as the sensing device.
  • This arrangement has the advantage that the disturbing signals are picked up where they are created. With this arrangement the disturbing signals received by the detecting coil are especially large.
  • a detecting coil is arranged in the area of the test space of the magnet system. This arrangement has the advantage that the disturbing signals are picked up where they are effective so that exactly those components of the disturbance which would lead to disturbances in the measurement can be compensated.
  • the cooling head in which the refrigerator has a cooling head containing a motorized drive, has a first flange which lies on a second flange which second flange in turn is connected to a neck formed on the outer shell of the magnet system.
  • the detecting coil is preferably arranged in the area of this neck, especially as a solenoid coil coaxially receiving the neck. This arrangement yields an especially compact and mechanically stable construction. Also with this arrangement the detatchability of the cooling head, for example for inspection, is not impaired.
  • a sensing device which picks up the mechanical disturbances produced by the refrigerator especially by measuring the acceleration or the vibration at a proper spot either on the refrigerator itself or on another point of the magnet system.
  • an electronic control device which conducts the output signal of the sensor to the coil serving for compensation purposes. Then the sensor signal can be correspondingly weighted, for example by being divided or multiplied according to what relationship exists between the measured disturbing signal and the compensation signal which is to be adjusted.
  • the sensor signal is modified by a characteristic line or graph since in doing this non-linear dependencies can be taken into consideration on one hand and on another hand changed measuring parameters can be suppressed.
  • These measuring parameters can for example be the basic field strength, an extraneous gradient modulation, a test temperature or the like.
  • a correcting coil can be arranged at different points of the magnet system, so long as it is effective in the test space.
  • Especially preferred in this case is an arrangement in which the correcting coil directly surrounds the test space. Thereby the disturbances emitted by the refrigerator are compensated at the spot at which they are effective.
  • the correcting coil in the area of the refrigerator itself so that the disturbances are compensated at the place of their origin so that the disturbances are entirely no longer transmitted to the magnet system or if they are then only in greatly weakened form.
  • a further construction of the invention involves the fact that the duct through the outer shell is formed as a vacuum tight sliding apparatus.
  • the cooling apparatus of the invention has the especial advantage that the superconductance of the magnet coil can be maintained while the refrigerator is mechanically serviced. In accordance with the invention this is accomplished by maintaining the vacuum in the cryostat so that the magnet coil is continually maintained at the required operating temperature of 4 K. Therefore the cooling device of the invention unites the advantage of a low evaporation rate in the associated refrigerator with the advantage of a long operating time of the superconducting magnet system in the "persistent mode".
  • the cooling arm is arranged in a tube belonging to the refrigerator and slidable in a neck formed on the outer shell.
  • Such an arrangement is especially advantageous because an effective seal can be made between the neck and the tube, using for example an O-ring and/or a bellows type sealing element which are available as standard parts and which make possible a good vacuum seal.
  • rods are provided as guides and displacement maintaining means, which rods are fastened to one of the flanges and slide in the other flange.
  • an index mark is provided to indicate the position of the displacement means corresponding to the moved out condition of the refrigerator. In this moved out condition the heat transfer between the cooled end section or the cooling finger of the arm of the refrigerator and the protective shield or the inner container of the cryostat is interrupted so that attainment of the mark shows that the service work can be carried out. In this way an especially simple start of the service work is possible.
  • the refrigerator with its outwardly lying head containing the actual cooling means is connectable by threaded means through a flange to the flange of the tube, in the case of basic servicing during which the magnet system indeed must be taken out of operation, the refrigerator head with the cooling arm can be dismounted without having to disassemble the mechanical guide of the tube in the neck of the outer shell.
  • the cooling arm runs to an end section and from there into a finger reduced relative to the end section so that the end section and finger in the inserted condition of the refrigerator stand in mechanical connection with two intermediate shields lying below one another. If the end section and the finger are brought to different temperatures, with this arrangement, which is especially easily adjustably insertable, one can cool with the refrigerator two protective shields or internal containers lying below one another to different temperatures.
  • the intermediate shield or container in the preferred form of the invention has a preferably cylindrical projection with a central bore whose diameter matches the outer diameter of the cooling arm or the cooling finger.
  • the bores and/or the end section or finger are provided with bevels at the faces facing one another.
  • this elastic mounting is obtained by having the mentioned cylindrical projection of the coupling part provided with radial slots and/or the stationary part of the projection provided at its foot with a reduced cross-section so that it is elastic in the radial direction.
  • a heating device is provided in the cooling arm with which it is possible to more quickly bring the temperature of the cooling arm or the refrigerator to a temperature at which the mechanical servicing, such as replacement of the sealing element, is possible.
  • the heating device and the parts to be serviced are arranged in an area of the cooling arm which in the pulled out state of the refrigerator lies outside of the outer shell of the cryostat so that the effect of the heating device has as little as possible influence on the cooled inner parts of the cryostat.
  • FIG. 1 is a cross-sectional view through one-half of a cryostat which is provided with one embodiment of a cooling device according to the invention
  • FIG. 2 is an enlarged view of a portion of FIG. 1;
  • FIG. 3 is a cross-sectional view through one-half of a cryostat which is provided with a cooling device comprising another embodiment of the invention
  • FIG. 4 is an enlarged view of a portion of FIG. 3;
  • FIG. 5a and 5b are views of a preferred embodiment of a coupling part which can be used in the arrangement of FIGS. 3 and 4, with FIG. 5b being a plan view of the part and with FIG. 5a being a sectional view taken on the line a--a of FIG. 5b.
  • FIG. 1 at 10 shows a superconducting magnet system using a refrigerator 11 for cooling interior protective shields or containers.
  • the refrigerator 10 is supplied, for example with high pressure gas, through a flexible conduit 13 from a compressor 12 spaced from the refrigerator.
  • the refrigerator 11 is made as an attachment consisting of a cooling head 14 as well as a first flange 15 formed on the head.
  • the first flange 15 rests on a second flange 16 which transitions into a neck 21 surrounding a cooling arm 18 extending from the refrigerator 11.
  • the neck 21 is formed on an outer shell 22 of the superconducting magnet system 10.
  • the outer shell 22 goes on the end sections of the superconducting magnet system 10, as a cover, with the end sections having a test opening 24 on the axis 25 of the magnet system. It will be understood that the illustration of FIG. 1 represents only one-half of the magnet system 10 which is formed so as to be generally rotationally symetric.
  • the outer shell 22 surrounds a first intermediate shield 26 standing in direct mechanical and therefore heat conducting contact with a container 27 containing liquid nitrogen 28.
  • the first intermediate shield 26 surrounds a second intermediate shield 29 which is connected with no container for liquid gas.
  • the second intermediate shield 29 surrounds however a container 30 for liquid helium 31.
  • a magnet coil 32 shown in the illustrated case as a solenoid coil.
  • the intermediate spaces 33 between the outer shell 22, the first intermediate shield 26, the second intermediate shield 29 and the container 30 are evacuated.
  • test space is indicated at 36 into which tests are brought for measurement with the magnet system 10, for example a test specimen on which high resolution nuclear resonance measurements are to be made.
  • the shields 26, 29 are provided with coupling parts 34, 35.
  • the cooling arm 18 at its end facing the magnet coil 32 first has an end section 38 which then transitions to a concentric finger 39 having a reduced cross-section with respect to the end section 38.
  • the cooling head 14 of the refrigerator 11 is provided with a first flange 15 which rests on the second flange 16 of the neck 21.
  • a seal made with an O-ring 40 is provided between these two flanges.
  • the end section 38 is in heat conducting contact with the coupling part 34 and the finger 39 in heat conducting contact with the coupling part 35.
  • the coupling parts 34 and 35 are formed as cylindrical projections 37 on the shields 26 and 29 through which projections central bores extend.
  • the outer diameters 44 and 46 of the end section 38 and finger 39 and the inner diameters 45 and 47 of the projections 37 are of such sizes that they produce a good mechanical fit and therefore a good heat transfer between the mentioned parts.
  • the end section 38 is brought to a temperature by the refrigerator 11 which is to be taken on by the first intermediate shield 26, for example a temperature of 80 to 100 K, while the finger 39 is cooled to the temperature to be taken on by the second intermediate shield 29, for example a temperature of 20 to 50 K.
  • the forward faces of the end section 38 and finger 39 are provided with bevels 48 and 50 while the outwardly facing faces of the projections 37 are provided with bevels 49 and 51.
  • the cooling head 14 of the refrigerator 11 is a motorized drive indicated by a movable piston 60 in FIG. 2.
  • the cooling head 14 has other movable parts, for example a piston rod, crank shaft and the like.
  • These mechanically moving parts of the motorized drive in two respects produce disturbances in the operation of the magnet system 10.
  • the movement of the metallic portions directly produce an induced magnetic field
  • the movement of the massive portions produce vibrations on the magnet system 10.
  • the cooling arm 18 extends directly away from the cooling head 14 and has a rigid mechanical connection through the end section 38 with the coupling part 35 and through the finger 39 with the coupling part 35 to the intermediate shields 26, 29 having direct proximity to the magnet coil. Vibrations originating in the area of the cooling head 14 are therefore directly planted in the direct proximity of the magnet coil 32.
  • a correcting coil 61 surrounding the test space 36 is provided in the test opening 24.
  • the supply signal for the correcting coil 61 is obtained from a detecting coil 62, which in the embodiment illustrated by the Figures is a solenoid coil surrounding the neck 21.
  • the output signal of the detecting coil 62 is transmitted through a conductor 63 to an electronic control device 64 which feeds the correcting coil 61 through a conductor 65.
  • the electronic control device 64 can amplify the signal from the detecting coil 62 or can attenuate it by a predetermined factor, that is altogether weighted, if such a linear relationship of the measured signal to the correcting signal is adequate.
  • control device 64 it will be understood, however, that it is also possible, in case of a non-linear dependency to provide a characteristic line or curve in the control device 64 if one or more of certain influences are to be taken into consideration.
  • a characteristic curve parameters of the control device 64 can also be taken into account, such as for example the employed basic field strength, extraneous modulation frequencies, a test temperature or the like.
  • the signal obtained from the detecting coil 62 is converted to a correcting signal according to a pregiven relationship and the correcting coil 61 is energized with this correcting signal.
  • a further correcting coil 66 is arranged coaxially around the detecting coil 62, which correcting coil 66 is controlled by the electronic control device 64 through the conductor 65a.
  • the same considerations as given above for the signal supplied to the correcting coil 61 also serve for the signal supplied to the correcting coil 66. That is, the correcting coil 66 is controlled in dependence on a correcting signal provided from the control device 64 which is produced from the signal emitted by one of the detecting coils, for example the detecting coil 62.
  • detecting and/or correcting coils are provided at one or more places so that the individual coils are effective in definite gradient directions corresponding to their arrangement.
  • Such plural coil arrangements are known in themselves and are moreover referred to as "shim-coils" whereby each individual or pair of such shim-coils is provided for compensating a known magnetic field gradient.
  • the refrigerator 11 is shown as an attachment and it consists of the head 14 having the first flange 15 formed thereon.
  • the first flange 15 rests on the second flange 16 which transitions into a tube 17 surrounding the cooling arm 18 extending from the refrigerator 11.
  • Rods are arranged in the second flange 16 to serve as displacement retainers 19 which slide in a third flange 20 located on the opposite side of the flange 16.
  • the third flange 20 is part of a neck 21 formed on the outer shell 22 of the superconducting magnet system 10.
  • the outer shell 22 goes on the end sections of the superconducting magnet system 10 as a cover part with the end sections 23 having a test opening 24 on the axis 25 of the magnet system 10. It will be understood that the illustration of FIG. 3 also represents only one-half of the magnet system 10.
  • FIG. 4 is a simplified representation in which the two embodiments are both sketched. The actual embodiments are each rotationally symetrical.
  • FIGS. 3 and 4 the refrigerator is shown in a moved out state.
  • the tube 17 slides in the neck 21 from the in-place position in which the second flange 16 rests on the third flange 20 to the illustrated position which preferably can be recognized by a mark 136 applied to one of the displacement retainers 19 which indicates the moved out state of the refrigerator 11.
  • the cooling arm 18 can next be brought to room temperature by means of a heating device 67 so that an exchange of mechanical parts, for example of seal elements is possible.
  • the heating device 67 is, as seen in FIG. 4, arranged in an area which lies outside of the outer shell 22 when the refrigerator is in its moved out condition, so that the adverse effect of this heating on the inner parts, especially on the protective shields 26 and 29 is kept to a minimum.
  • the refrigerator When the mechanical service work on the refrigerator 11 is completed the refrigerator can be pushed back from the position shown in FIGS. 3 and 4 to its working position.
  • FIG. 5 illustrates an embodiment of a coupling part which for example can be used to form the coupling part 35, with FIG. 5a being a sectional view taken along the line a--a in FIG. 5b.
  • the projection 37 is provided with the already mentioned central bore having the inner diameter 47, from which radial slots 52 pass through the projection 37. If the foot portion of the remainder of the projection 37 is reduced by means of a countersink with a diameter 53, which is greater than the diameter 57, there remains an elastic or springy crown type holder into which the finger 39 can be driven. Through the elastic holding of the finger 39 there is obtained a clamped connection between the projection 37 and the finger 39 giving an especially good heat conducting transfer.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Electromagnetism (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Containers, Films, And Cooling For Superconductive Devices (AREA)
  • Details Of Measuring And Other Instruments (AREA)
US06/577,699 1983-02-09 1984-02-07 Cooling device for a low temperature magnet system Expired - Lifetime US4535595A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE3304375 1983-02-09
DE19833304375 DE3304375A1 (de) 1983-02-09 1983-02-09 Kuehleinrichtung fuer ein tieftemperatur-magnetsystem
DE3308157 1983-03-08
DE19833308157 DE3308157A1 (de) 1983-03-08 1983-03-08 Kuehleinrichtung fuer ein tieftemperatur-magnetsystem

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US4535595A true US4535595A (en) 1985-08-20

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US06/577,699 Expired - Lifetime US4535595A (en) 1983-02-09 1984-02-07 Cooling device for a low temperature magnet system

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US (1) US4535595A (de)
EP (1) EP0116364B1 (de)
JP (1) JPH0634012B2 (de)
DE (1) DE3460231D1 (de)

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US4704871A (en) * 1986-04-03 1987-11-10 The United States Of America As Represented By The United States Department Of Energy Magnetic refrigeration apparatus with belt of ferro or paramagnetic material
US4713945A (en) * 1985-07-30 1987-12-22 Elscint Ltd. Turret for cryostat
US4765153A (en) * 1986-02-12 1988-08-23 Kabushiki Kaisha Toshiba Cryostat with radiation shields cooled by refrigerator
US4777807A (en) * 1986-09-09 1988-10-18 Oxford Magnet Technology Limited Cryostat assembly
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US6396272B1 (en) * 1999-01-21 2002-05-28 Siemens Aktiengesellschaft Method of cancelling lorentz force-produced oscillations in a gradient tube, and magnetic resonance imaging apparatus operating according to the method
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DE10221640A1 (de) * 2002-05-15 2003-12-04 Siemens Ag Verfahren zur Vibrationskompensation bei Kernspintomographen
US20050229620A1 (en) * 2004-04-15 2005-10-20 Oxford Instruments Superconductivity Ltd. Cooling apparatus
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US20070216506A1 (en) * 2006-01-17 2007-09-20 Takeshi Nakayama Superconducting electromagnet
US20080027666A1 (en) * 2006-07-31 2008-01-31 Michael Schenkel Device and method for compensation of magnetic field disruptions in highly homogeneous magnetic fields
US20120242336A1 (en) * 2011-03-25 2012-09-27 Philippe Stauffenegger Compact cryogenic NMR sensor with integrated active cooling device
GB2509087A (en) * 2012-12-19 2014-06-25 Siemens Plc Sealed rotary drive arrangement, providing drive into a high-pressure gas vessel
GB2523762A (en) * 2014-03-04 2015-09-09 Siemens Plc Active compensation of magnetic field generated by a recondensing refrigerator
DE102014218773A1 (de) 2014-09-18 2016-03-24 Bruker Biospin Gmbh Automatische thermische Entkopplung eines Kühlkopfs
CN106531395A (zh) * 2015-09-09 2017-03-22 三星电子株式会社 超导磁体设备
US10839998B2 (en) * 2017-10-09 2020-11-17 Bruker Switzerland Ag Magnet assembly with cryostat and magnet coil system, with cold reservoirs on the current leads
DE102019112718A1 (de) * 2019-05-15 2020-11-19 Maschinenfabrik Reinhausen Gmbh Verfahren zum Durchführen einer Umschaltung von mindestens einem Schaltmittel eines Betriebsmittels und Antriebssystem für mindestens ein Schaltmittel eines Betriebsmittels

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IL68138A (en) * 1983-03-15 1988-01-31 Elscint Ltd Cryogenic magnet system
DE3628161A1 (de) * 1986-08-20 1988-02-25 Spectrospin Ag Vorrichtung zum kompensieren von zeitvarianten feldstoerungen in magnetfeldern
EP0284874A1 (de) * 1987-04-02 1988-10-05 General Electric Company Thermische Schnittstelle für das Zusammenschalten eines Kryokühlers mit einem bilderzeugenden Magnetresonanzkryostat
JPH01243503A (ja) * 1988-03-25 1989-09-28 Toshiba Corp 磁気共鳴イメージング装置用静磁界磁石
US5522226A (en) * 1995-09-12 1996-06-04 General Electric Company Positive retraction mechanism for cryogenic thermal joints
CN106679228B (zh) * 2016-11-18 2021-11-23 南方科技大学 制冷器件及其制备方法

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DE10221640B4 (de) * 2002-05-15 2007-06-21 Siemens Ag Verfahren zur Vibrationskompensation bei Kernspintomographen
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DE102004023073B3 (de) * 2004-05-11 2006-01-05 Bruker Biospin Gmbh Magnetsystem mit abgeschirmten Regeneratorgehäuse und Verfahren zum Betrieb eines solchen Magnetsystems
US7235975B2 (en) 2004-05-11 2007-06-26 Bruker Biospin Gmbh Magnet system with shielded regenerator housing
US20070216506A1 (en) * 2006-01-17 2007-09-20 Takeshi Nakayama Superconducting electromagnet
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US7474976B2 (en) 2006-07-31 2009-01-06 Bruker Biospin Ag Device and method for compensation of magnetic field disruptions in highly homogeneous magnetic fields
US20080027666A1 (en) * 2006-07-31 2008-01-31 Michael Schenkel Device and method for compensation of magnetic field disruptions in highly homogeneous magnetic fields
US20120242336A1 (en) * 2011-03-25 2012-09-27 Philippe Stauffenegger Compact cryogenic NMR sensor with integrated active cooling device
US8896312B2 (en) * 2011-03-25 2014-11-25 Bruker Biospin Ag Compact cryogenic NMR sensor with integrated active cooling device
GB2509087A (en) * 2012-12-19 2014-06-25 Siemens Plc Sealed rotary drive arrangement, providing drive into a high-pressure gas vessel
GB2523762A (en) * 2014-03-04 2015-09-09 Siemens Plc Active compensation of magnetic field generated by a recondensing refrigerator
DE102014218773A1 (de) 2014-09-18 2016-03-24 Bruker Biospin Gmbh Automatische thermische Entkopplung eines Kühlkopfs
US10203067B2 (en) 2014-09-18 2019-02-12 Bruker Biospin Gmbh Automatic thermal decoupling of a cold head
CN106531395A (zh) * 2015-09-09 2017-03-22 三星电子株式会社 超导磁体设备
CN106531395B (zh) * 2015-09-09 2018-06-15 三星电子株式会社 超导磁体设备
US10839998B2 (en) * 2017-10-09 2020-11-17 Bruker Switzerland Ag Magnet assembly with cryostat and magnet coil system, with cold reservoirs on the current leads
DE102019112718A1 (de) * 2019-05-15 2020-11-19 Maschinenfabrik Reinhausen Gmbh Verfahren zum Durchführen einer Umschaltung von mindestens einem Schaltmittel eines Betriebsmittels und Antriebssystem für mindestens ein Schaltmittel eines Betriebsmittels

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JPH0634012B2 (ja) 1994-05-02
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JPS6069540A (ja) 1985-04-20
DE3460231D1 (en) 1986-07-24

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